I Can See Clearly Now: Fisheye Cameras and Dewarping

Their ability to capture images that could be missed by a traditional fixed camera or even a pan-tilt-zoom only model makes them critical for security applications where sweeping views are required. For example, 360-cameras excel within settings like an open concept retail store where a single camera can be observing all directions at the same time. The cameras have also proven useful beyond the retail setting in college lecture halls, casinos, office lobbies, hallway intersections and enclosed parking garages, to note a few.

Fisheyes are also touted for their wide dynamic range, as well as savings on bandwidth and storage usage while still capturing full resolution images.

The image produced isn’t a typical, flat one, but rather is round and distorted, the result of capturing an ultra-wide field of view. To make the images usable, they need to be flattened out, or dewarped. In most cases, the dewarping process takes place at the client, such as the NVR, PC, or server depending on where the client software that handles the dewarping of the images resides.

A few manufacturers offer cameras that can natively dewarp the images. Thus, the video can be viewed in the more traditional format, but with the benefit of getting all the detail that a 360-degree view provides. Having the camera perform the dewarping process relieves the burden and reliance for this action from the recorder and client, bypassing the step of having to dewarp the recorded view separately.

In dewarped or flattened images, security personnel can hone in on details that are important to the situation, while also having the option of looking at the larger picture. If you think about a 360-degree image as four quadrants — north, south, east and west — consider that when an event occurs, you have the option of retrieving an image that shows action in the north quadrant only, where you believe the suspect activity occurred. There may be something that took place elsewhere that you now want to check out, and so you can playback images that capture activity in the south, east and west quadrants as well. For this reason, fisheye cameras are a cost savings as they can take the place of four cameras when placed at the intersection of hallways.

Having quick access to a normalized view of a situation, especially when an event is occurring, makes dewarping at the camera level a convenient tool for seeing everything the video has to offer.

In what ways are you using Fisheye Cameras?Please leave me a comment below.